Cement-based plaster - what is it?
Any plaster solution consists of three main components:
- bonding materials - it can be plaster, clay, cement, lime and so on;
- fillers - sawdust, shavings, slag, screenings, sand and so on;
- water.
What type of binder and aggregate to choose depends on the type of surface to which the mixture is applied, and also on the environment and operating conditions. For indoor and outdoor premises with a moisture content of less than 60%, plaster is usually used on a cement base.
Cement mortar for plaster is prepared from cement grade 400, to it add sand at the rate of 1.5 to 5 parts. The correct solution is obtained by thorough mixing with water of all binding materials, the composition of the cement plaster is of paramount importance here. The ideal kind of mortar, suitable for finishing works, resembles a dough. In the absence or excess of any components, the final result will be substandard. Thus, plastering of walls with cement mortar, in which proportions are not observed - there is no or insufficient filler - will give cracks when hardening.
Also very important in the manufacture of the working test is the addition of water, which is simultaneously responsible for the plasticity of the solution and affects the ability to solidify. Therefore, professionals add water in small quantities by spraying.
Types of cement plaster
Some parts of the external and internal surface of the walls are subjected to different loads during the operation, so different plaster compositions are needed for their finishing. The type of solution is determined by the main astringent component.
- Cement-sand plaster is used for both indoor and outdoor finishing works in rooms or in a climate with a low moisture content.
- Cement-lime plaster is the most popular composition for finishing rooms with high humidity( baths, kitchens, internal wooden surfaces, external concrete or stone walls, socles, cornices, other projecting parts).
- Cement or gypsum plaster is also used for finishing plaster partitions. In this case, gypsum is used to increase the drying speed of the solution.
Cement consumption for plaster, as well as the grade of the material used, depends on the composition of the layer being treated and the nature of the work to be performed. So, with a spray and cover, its amount increases by 20-30%.
Dressing of cement plaster
To ensure long life of the protective layer and to prevent the development of the fungus, the cement plaster is etched with a neutralizing solution, as well as the antibacterial treatment of the hardened surface. In addition, the cement-lime mortar for plaster can be turned into an original type of decorative relief by treatment with a solution of hydrochloric acid, which after a few minutes washed with water.
In any case, such work must be done in compliance with all safety standards, using special protective equipment. More detailed understanding of the nuances of the technology of plastering walls with cement mortar will help the video, which you will find on our website.